Instrument cover



Se t. 30, 1952 w. R. TRIPLETT 2,612,132

INSTRUMENT COVER Filed Sept. 15,1950

'2 4 e, OD.C.VOLTS0 5 INVENTOR WILLIAM R; TRIPLETT W ATTORNEYS.

Patented Sept. 30, 1952 UNITED PATENT" 1 The Triplett ;-Electrical Instrument Company, Bluffton, Ohio, acorporation of Ohio Application September 15, 1950, Serial ism-185,053- 1 I I This invention relates to indicating devices, such as electrical instruments, meters, andthe like, and particularly to the indicating scale and indicia therefor. I I I the dial of. the instrumentis devoidof any mark- [10 claims. (crime-1 14) ings and the-scale and indicia therefor and any necessary legends are applied directly to the detachable transparent member. r

The foregoing objects and other objectsand In connection with most indicating in'struadvantages will become more apparent upon refments, which it is understood will include elece'rence' to the following description taken in con trical instruments such as voltmeters, ammeters, nection with the accompanying drawings in and the like, pressure indicating devices, and which: r other such mechanisms as are used in industry, Figure 1 is a perspective view showing an indithere is generally provided a calibrated scale eating instrument constructed in accordance wit bearing indicia vover which a movable pointer the teachings of this invention? I sweeps as the instrument is actuated by the stim- Figure 2 is a sectional view indicated by line ulus applied thereto. j I 2-2 on Figure l and showing theappearanoe of Heretofore when a multiple purpose instruthe auxiliary cover member of this invention in ment, such as a multiple scale voltmeter or 15 section; I I I 1 ammeter or a voltameter was provided, the cali- Figure 3 is a perspective view showing a modibrated scale referred to above was either pro fied form of my invention; vided with multiple sets of indicia, or else multiple Figure 4 is a sectional view indicated byline calibrated scales were provided, each having their 4- 4 on Figure 3 showing the manner in' which own indicia. I I the main covermember'and auxiliary cover mem- Also, in many instances it is desired to convert her" are retained together; I an instrument from one range to another or from Figure 5 is a sectional view taken on line 5-5 one type of measuring duty to anotherQand this of Figure 3 and showing an arrangement progenerally requires that a new scale be provided. vid d detaching the auxiliary member from Inasmuch as such scalesare generally placed t e ma cove m I directly on the dial of'the instrument, "replace- F gure 6 iS ap sp c e View p r ly ec o ment of the scale requires that the instrument ofstill another modified form of my invention; be dismantled and the dial replaced with another. and i I I g .r

It is an object of the present invention to prore '7 i a fragmentary w Showing a Still vide a simple and inexpensive means of overfurther form which the auxiliary member of my coming the difiiculties referred to above in coninve t n may take a d-in ud n a l s-s ap d nection with the operation of instruments over D O the p lw fl magnifying th ca e and more than one range and for more than one type indicia of the instrument. I I of service. l Referring to the drawings somewhat more in Another object of this invention is to provide detail, Figure 1 shows an exploded perspective an arrangement whereby the calibration of the viewfof an electrical instrument constructed dial of an instrument can be modified without according to'this invention, but it will be undersma theinstrument. stood that'the invention obtains equally in con- A still further object is to provide an instrunection with all types of indicating instruments ment wherein e n e of Operation and the 40 and devices, and theel'ectrical instrument shown calibration of the instrument can be changed s merely m y Qf one of th many uses t without in any way disturbing the interior of the which myinvention can be put. instrument, whereby it can remain sealed against In Figure 1.:the instrument illustrated comforeign substances-at all times. I I prises a casing 10 having a flange lz through In general the objects of this invention are which mounting studs |4may extend t accomplished by providing the instrument with pose of supportingfthe instrument o panel dial having a al a d Scale therein Over Terminal posts may extend out the back of the which the pointer of the instrument sweeps, but i t t as di t at 5, for t e os Which calibrated Scale i devoid f le n s d of making electrical connections to the movement indicia, and providing the legends and indicia on of the instrument. I H r, a separate transparent member that can-readily The casing I0 isopen at one side and there is be attached to or detached from the instrument a dial l8 mountedthereover, bearing, a scale 20-. in proper alignmentwith the calibrated scale; The scale 20 is of a conventional type, except In another form which my invention may take that it is devoid of all indicia or legends.-- Mow able, along thegscale is a pointer 22 secured to by the indicia on cover member 36 will always properly register with the scale on dial [8.

The main cover member 26 may, of course, be provided with the usual zero adjusting screw 42, and auxiliary cover member 36 may be formed to provide access to the screw by the aperture 44.

example, in the manner illustrated in the copending application Serial No. 137,950, filed January 11, 1950, in the name of William R. Triplett, and assigned to the :same the present application.

In the application referred to, the cover mem-- ber is secured to the periphery .of-the dial,.wh-ic h, in turn, is secured to the instrumet movement,

and which, in its turn, is secured in the in- 'other shape than shown.

Extending about the periphery of cover member 26 is a, ledge or shoulder 28, and there is provided anaux-iliary cover-member 36, having rearWardly-extending flange 32 that is adapted for closely :fitting about the periphery of the shouldered part 28 of cover member 26.

The length of flange 32 ;on the auxiliary cover member 30 abuts the outer face of the main cover member 26, and the rear edge of flange 32 abutsthe shoulder about main cover member 26, whereby the two'cover members when assembled present a flush surface over the entire exterior;

According .to this invention, the auxiliary transparent covermember 30 beats indiciathereon, as indicated at 34,..and may also bear any desirable'legend, as indicated at 36. These indicia and legends may be associated with auxiliary cover member 30 in any suitable manner, such as by being appliqued thereto, by being etchedtherein, by being formed integrallywith the cover member during molding operation, or in any other suitable manner that will provide for a permanent association of'the-indiciarand cover member- .Asfillustrate'd, the indiciaand legend are on the inner'surface of the auxiliary. cover member, and this hasthe advantage of positioning the in'di'cia and legends in a protected location, whereby they are not" easily scratched .and whereby the cover of the instrument can "readily be cleaned at anytime without any danger of damaging the'said-indicia and legends.

Preferably, thetwo cover members are-so arranged that they'will'be held tightlytogether at-alltimes, but'will be readily detachable from each other. To this end, I provide the cover members with interfitting-portions,such as the notch 38 aboutthe periphery-of main cover member 26, which is adapted for engagement with lip formed in the periphery of auxiliary cover member 36. This lip and notch -arrange-' ment may occur-at one'or more locations about the 'peripheries-ofthe cover members, and not only serves as a means for holding the cover members -together,'but also-provides a means for locating the cover members relatively, where- :assignlee :as

auxiliary cover member is indicated at 52.

Turningnow to Figure.f3, there :is shown a somewhat modified arrangement wherein the main cover member is indicated at 56, and the In Figure 3 the auxiliary cover member extends over only a portion of the main cover member and:is:detachablypsecured thereto in some suitable-mannerras by forming the main cover member'wi-th a recess54 having a beveled edge 56. The outer periphery. of the auxiliary cover member is then correspondingly beveled, as at 58,

so :thatit can be snapped into position on the main cover member in .much the same manner as a watch :crystal is snapped intopositionon itsbezel. v

In order to facilitate the detachment of the auxiliary cover member from the main cover member, one or both of the members may be formed with a notch, as at 60, and which, as willbe seen in Figures 3 and 5, provides ready means for inserting a knife blade, screw driver tip, or othersuitable tool, between the .cover members for snapping the auxiliary cover member out. I

In Figure 6, I illustrate a still further modification, wherein the instrument case may be provided with a mounting ring 62 which may be of metal or plastic, as desired, and which forms a bezel ring into which may be snapped a transparent cover member 64 hearing indicia and legends for registration with the scale of the instrument.

In the modification of Figure 6 the advantage obtains that the calibration of the instrument scale can readily be changed at any time, merely by replacing, the transparent cover member 64, but the disadvantage is present that every time the cover member is removed, the interior of the cover member is exposed.

InFigure '7 there isillustrated a still further modified arrangement wherein the auxiliary transparent member 66 bearing the indicia and legends, asindicated, is provided with a lensshapedpart- 68 whichserves-to magnify the scale an-dindicia, thereby making the reading of ,the instrument; easier. The-arrangement of Figure 7 is adapted for being incorporated in any-of the above described, modifications.

From theforegoing, it will be seen that what Ihaveinvented. is a relatively simple and inexpensive, but highly eifective arrangement for providing multiple purpose instruments or instrustruments which can readily be converted from one use to another, ate-very little expense or trouble. I

The invention is particularly useful in connection with electrical instruments because substantially all the movements of ammeters, voltmeters, and ohmmeters, and multiple purpose testing instruments such as are used in radio and thelike, are constructed of a substantially conventional milliammeter movement, usually a movement in which one milliampere through the instrumentcoil will give full scale deflection, and the adaptation of this instrument to these many uses is-accomplished by the use of series and parallel resistors. i

It :will be seen that this invention will. permit an instrument movementof ithis type to be placed in a case with an uncalibrated scale, andto be adapted to substantially any -purpose involving the measuring of a current flow without opening the instrument case merely by connecting the proper resistors or shunts to the terminallfiand by placing the proper auxiliary cover member on the face ofthe instrument.

Further advantages to be had by utilizing the instrument arrangement of my invention are that the instruments may be produced in greater quantity and can be offered for sale at lower cost. Further, a distributor or large user is enabled to limit the stock of instruments which he must carry to only a few, and sometimes only one basic movement, and merely provide a relatively low cost inventory of detachable cover parts and shunts and resistors in order to adapt the instrument when a particular use is desired.

In the laboratory and in production lines the instruments may be permanently installed and may be adapted for use to substantially any circumstance on short notice. In this instance also the wide range of flexibility and adaptability of the instrument will materially reduce the number of instruments that must be carried in stock.

A material advantage in connection with my invention is that instruments having special scales or indicia thereon can readily be supplied, but the instrument at the same time has the quality of nonobsolescence because it can readily be changed to operate on another scale or be altered easily to adapt it to another type of service.

It will be evident that while I have illustrated and described in particular an arrangement where the scale of the instrument is applied to a dial plate behind the movable pointer of the instrument, the said dial plate could be free of any markings whatsoever, and not only the indicia and legends applied to the transparent member, but the scale as well, thereby making it possible to adapt the instrument to any circumstances for special applications and the like.

While this invention probably finds its greatest field of use in connection with electrical instruments, I do not intend to limit myself to that application alone, but desire to comprehend within my invention all such adaptations, modifications, and changes as may be considered to come within the spirit and scope of the appended claims.

I claim:

1. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale thereon; a transparent cover mounted on the said one face of the case and enclosing said dial and pointer, and a second transparent cover detachably mounted on said first cover and bearing indicia adapted to register with the scale on said dial.

2. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale thereon; a transparent cover mounted on the said one face of the case and enclosing said dial and pointer, and a second transparent cover detaehably mounted on said first cover and bearing indicia adapted to register with the scale on aid dial, and means to hold said first and second covers together in a fixed relative position. v

3. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale thereon; a circular transparent cover mem- 6, her-mounted on the said oneiface of the, case and enclosing? the dial and pointer; an annular ledge formed about the periphery of said cover member, and an auxiliary transparent cover member having an annular flange adapted to engage. theled'ge detachably -tov holdithesaid cover members together,; andfindicia on :the inner. face of a said auxiliary .cover .member to register withsaid him an indicatingiginstrument: having ai-case with: a dialron one face. having a scale thereon with a dial on one face having a scale thereon Y and a pointer movable over the dial along the scale thereon; a shallow, cup-like transparent cover member mounted on the said one face of the case and enclosing said dial and pointer, and a second shallow cup-like transparent member adapted to fit closely over and about the outer face of said cover member and having indicia on its inner face for registration with the calibrations of said scale, said members presenting an external flush surface when placed together.

6. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale thereon; a shallow, cup-like transparent cover member mounted on the said one face of the case and enclosing said dial and. pointer, and a second shallow, cup-like transparent member adapted to fit closely over and about the outer face of said cover member and having indicia on its inner face for registration with the calibrations of said scale, and means comprising interfitting portions on said members to retain the said members tightly together and to predetermine a relative position thereof.

7. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale; a transparent cover mounted on the said one face of the case and enclosing said dial and pointer, a transparent member mounted on the face of the cover over at least the area of the dial bearing the scale and having indicia on its inner face to register with said scale, and interfitting parts on the cover and member detachably to retain the member in a predetermined position on the cover.

8. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale; a transparent cover mounted on the said one face of the case and enclosing said dial and pointer, a recess in the face of the cover over the area of the dial bearing the scale, and a transparent member adapted for being detachably retained in said recess and bearing indicia on its inner face to register with said dial.

9. In an indicating instrument having a case with a dial on one face having a scale thereon and a pointer movable over the dial along the scale; a transparent cover mounted on the said one face of the case and enclosing said dial and pointer, a recess in the face of the cover over the area of the dial bearing the scale, and a trans- .7 gpa-rent memb'er 'adapted for'ebeing edetachablyzrertained-in said recess and hearing indicia aonrits inneriface'to'register with'said diaLv-saidmember and'cover presenting ;a.-substant1a11y:flush surface =when assemb1ed.

10. A :cover :for anxindicatmg instrument hav- .ing an indicia :free scale and a zpointermovable along the scale comprising :a-:two-.part assembly. one part being adapted for directly mountingzon :the: instrument, *andzthe 50131161 part :being detachably ;.mounted :on zthesaid one part :and bear- :mg tn'diciazto register with dzhe gscale :ofthe instrument.

UNITED STATES ,PATENTS "N umber "Name Date 2,285,658 Hitchcock June -9, 194-2 2,528,640 Coleman Nov. '7, I950 

